'Dawn of the Planet of the Apes': Why Apes Can't Speak Like Humans

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In the new film "Dawn of the Planet of the Apes," a brilliant,
mutant chimp named Caesar forcefully yells "Go!" at a group of
humans who wandered into the ape population's forest. His deep,
guttural voice startles the people, but his vocalizations are
even more surprising.

"One school [of thought] believes that chimpanzees simply don't
have the vocal apparatus, and others believe they do, but
language as we know it just hasn't emerged or evolved," said Marc
Bekoff, an ecologist and evolutionary biologist at the University
of Colorado in Boulder. [ 8
Humanlike Behaviors of Primates ]

Humans have vocal tracts that move freely and can be well
coordinated, but the larynx muscles and vocal cords of apes don't
have that same movement or coordination, according to the
Max Planck Institute for Psycholinguistics.

It's also possible that apes haven't evolved to speak like humans
because they haven't needed to.

"As a biologist, I would always say, 'If they needed to be able
to speak like we do in a language like we have, they would,'"
Bekoff told Live Science. "That doesn't mean they don't have
their own language. All the
great apes — of course, including chimpanzees — have very
complex communication systems. They communicate using
vocalizations, facial expressions, gestures, postures, gait …
They can send very subtle signals with a lot of nuances by
varying any one of [those] components."

Some primates have learned how to communicate in specific ways
with their human handlers. One famous case is
Kanzi, a 33-year-old bonobo. Scientists who worked with Kanzi
think bonobos can understand English.

"Kanzi, for example, could figure out human sentences — even
nonsense sentences," Bekoff said. Someone once asked Kanzi to
take a microwave outside, and he followed that request, even
though it wasn't a common kind of command, Bekoff added.

Yet, even though Kanzi could understand and carry out directions
from humans, the bonobo's responses "were not anything close to
being verbal," Bekoff said.

Some scientists think that although chimps and other great apes
can learn vocabulary well enough to express their wants and
needs, they still don't necessarily understand syntax, a key
component of human language.

Herbert Terrace, a primate cognition scientist at Columbia
University, has found that chimps cannot combine words in
different orders to create new meaning — a skill that humans
understand from a young age.

Apes may not be able to speak like humans, but this probably
doesn't have anything to do with the animals' intelligence,
Bekoff said.

"A lot of animals that we don't think are particularly bright —
because we have such a perverted sense of what it means to be
bright — communicate in sophisticated ways," Bekoff said. For
example, prairie dogs have a very complex way of communicating,
using different vocalizations to signal a threat from various
predators, Bekoff added.

In " Dawn
of the Planet of the Apes," Caesar is the most fluent English
speaker of the apes in the film, but other chimps, gorillas and
orangutans seem to pick up on some of the leader's novel
vocalizations. Learned behavior has been observed in real-life
chimp communities, where some apes have picked up American Sign
Language, Bekoff said.

"A lot of [chimps] learned sign language not by being explicitly
taught, but by observing the other chimpanzees," Bekoff said.
"They were acquiring American Sign Language by just observation,
and somehow — to me, it's remarkable — they could then put
meaning to the different signs."

The movie "Dawn of the Planet of the Apes" is out in theaters
now. Bekoff is the author of the book " Why Dogs Hump and Bees
Get Depressed: The Fascinating Science of Animal Intelligence,
Emotions, Friendship, and Conservation."